Bacterial & Fungal meningitis

Question 1

Basically what is meningitis?

Answer 1

• infection of CSF
• Acute fever, headache, neck stiffness +/- rash
• Fully conscious, no focal neuro signs -Usually viral can be bacterial

Question 2

What is encephalitis?

Answer 2

• Infection of the brain tissue
• Acute fever, headache, neck stiffness
• Altered conscious level, seizures, +/- focal neuro signs
• Usually viral
• Herpes simplex most common
• All ages 1/2 in >50yrs
• Diagnosed by viral nucleic acid in CSF

Question 3

What is a brain abscess?

Answer 3

• Abscess within brain tissue
• Insidious onset of fever, headache, +/- neck stiffness
• +/- altered conscious level, seizures, focal neuro signs
• Usually bacterial may be parasitic

Question 4

How can micro-organism get into the brain/meninges?

Answer 4

• Blood-borne invasion (blood-brain barrier or blood-CSF barrier)
• Peripheral nerves

Question 5

What type of meningitis is found in university students? How can it present?

Answer 5

• Neisseria meningitidis
• Natural habitat nasopharynx
• Septicaemia w/purpuric rash
• Septicaemia w/meningitis
• Pyogenic (purulent) meningitis w/no rash
• Fulminant septicaemia

Question 6

What are factors allowing the intravascular survival and infection by N.meningitidis?

Answer 6

• Capsule: protects against complement-mediated bacteriolysis & phagocytosis
• Acquisition of iron from transferrin
• Able to cross blood-brain barrier & multiply in subarachnoid space

Question 7

What are the clinical implications of meningococcal septicaemia?

Answer 7

• Echymoses
• Eyes w/intraocular haemorrhage
• Thrombosis & gangrene of the fingers
• Haemorrhagic adrenals

Question 8

What is the treatment & prevention for Neisseria meningitidis?

Answer 8

T= penicillin, ceftriaxone, cefotaxime, early treatment, intensive care
P= vaccination

Question 9

Describe Haemophilus influenzae

Answer 9

• Unable to grow in absence of blood/ certain components
• Small, pleomorphic gram -ve cocco-bacilli
• Some strains produce a polysaccharide capsule
• Type B cause most invasive disease (meningitis)

Question 10

How is Haemophilus influenzae treated?

Answer 10

• Ceftriaxone, cefotaxime, ampicillin

- Chemoprophylaxis of contacts of invasive disease= rifampicin

Question 11

Describe strep pneumoniae

Answer 11

• Gram +ve cocci
• Cells in pairs
• Requires blood/serum for growth
• Normal habitat= human rest tract
• Transmission via droplet spread
• Optochin test
• All ages (more common in elderly & immunocompromised)

Question 12

What is the treatment for strep pneumoniae?

Answer 12

• Ceftriaxone, cefotaxime, penicillin resistant

- Conjugate vaccine against common serotypes

Question 13

Describe steroid use for meningitis in adults

Answer 13

• Dexamethasone 0.15mg/kg IV every 6 hours 2-4days
• Causes dec levels of vancomycin in CSF so use rifampicin as well
• Steroids for S.pneumoniae not meningococcal meningitis-no effect
• Given shortly before 1st dose of antibiotics

Question 14

Describe neonatal meningitis

Answer 14

• Group B beta-haemolytic strep
• Escherichia coli
• Listeria monocytogenes
• Early onset usually septicaemia
• Late onset usually meningitis
• Treatment= cefotaxime, ampicillin & gentamicin

Question 15

What are complications of meningitis?

Answer 15

• Death
• Overwhelming sepsis
• Raised intracranial pressure
• Deafness
• Delayed development
• Seizures
• Stroke
• Hydrocephalus

Question 16

What are types of lymphocytic meningitis?

Answer 16

• Viral meningitis (enteroviruses, herpes simplex)
• Spirochete (treponema, borrelia)
• Polio can cause meningitis that can lead to paralysis
• TB meningitis (RF: alcoholic, immunocompromised, from endemic area)

Question 17

Describe a brain abscess

Answer 17

• Usually bacterial
• Spread of organisms from adjacent structures (strep anaerobes from middle ear or sinuses)
• Bloodstream spread (staph aureus)
• Prolonged course of antibiotics

Question 18

Describe cryptococcal meningitis

Answer 18

• Cryptococcus= yeast seen in CSF (w/indian ink stain)
• Common problem in late stage HIV
• Insidious onset
• Lymphocytic meningitis
• Prolonged treatment with amphotericin, flucytosine/fluconazole

Question 19

What is Japanese encephalitis virus?

Answer 19

• Commonly affects children
• 1/3 die from acute illness, 1/3 severe neuro disability
• Vaccination available

Question 20

What is rabies encephalitis?

Answer 20

• Common in many countries
• Dog,fox,bat bites
• 100% mortality
• Prevented by vaccine

Question 21

Describe Clostridium tetani and its treatment

Answer 21

• Gram +ve spore forming bacilli (drumsticks)
• Strict anaerobe
• Widespread in soil
• Non-invasive but produces tetanospasmin
• Antitoxin (horse or human)
• Penicillin or metronidazole
• Drugs for spasm, muscle relaxants, resp support
• Prevention= toxoid

Question 22

What is the mechanism of action of tetanus?

Answer 22

1) Toxin gene on plasmid is encoded into cell
2) Toxin spreads via bloodstream & retrograde transport
3) Binds to ganglioside receptors blocking release of inhibitory interneurones
4) Convulsive contraction of voluntary muscles

Question 23

What are the signs &symptoms of tetanus?

Answer 23

• Lockjaw/trismus
• Tonic muscle spasms
• Opisthotnus
• Resp difficulties
• Cardio instability
• Sympathetic NS affected

Question 24

How will the following change in a TB, Viral, bacterial & cryptococcus infection:
Cell count
Cell type
Glucose levels
Protein levels

Answer 24

• B: cc=INC(>200) ct= polymorphs g=DEC(2) p=INC

- V: cc=INC(20-200) ct=lymphocytes g=NORM/RED p=NORM/INC